BOSTON — Massachusetts has a cannabis conundrum.

State law requires every county to have a dispensary for medical marijuana, but federal regulations forbid the drug from being transported across U.S. waters. That leaves the tourist havens of Martha’s Vineyard and Nantucket potless unless someone gets a license to grow it legally on the islands.

Despite their small size, both islands are their own counties. State officials suggest the federal restrictions could add to the challenge of opening medical marijuana outlets on both, or either, of the islands in the near future and may preclude the possibility of the islands sharing a dispensary.

One approach to establishing dispensaries on the islands would be to license an operator to cultivate and sell pot at the same location, perfectly legal under the state law. Geoff Rose, a transplanted New Yorker who has lived on the Vineyard for 14 years, applied to the state health department for a license to do just that.

The federal waters obstacle, he said, is “an impediment to those who thought they could cultivate off-island and transport here, but I don’t see it as an impediment at all.”

His company, Patient Centric of Martha’s Vineyard, originally applied last year under the since-discarded licensing process but fell short of meeting the state’s criteria at the time. He hopes his renewed bid will get a more favorable reception, allowing him to open by next year in the town of West Tisbury.

Rose was unsure of the level of demand for medical marijuana on the Vineyard but noted the island is to home to many seniors and retirees who have cancer or other chronic conditions. Doctors have certified more than 14,000 people statewide to use medical marijuana, but the state doesn’t have a breakdown by county.

Advocates for the therapeutic use of cannabis are pushing for federal legislation that would clear up gray areas where state and federal laws intersect.

“No matter how many states do it, we are still going to have some of these weird loopholes that people fall into,” said Christopher Brown, spokesman for the Washington, D.C.-based Americans for Safe Access.

Massachusetts has struggled in general to implement a 2012 voter-approved law that allows patients with certain chronic or painful conditions to register with the state and use marijuana.

The law permits as many as 35 dispensaries, but the first opened only recently, in Salem. Republican Gov. Charlie Baker, who …Read More